FR3128140A1 - Hybrid Ultrasonic Non-Destructive Test Device Monolithic Rotating Optical Assembly Laser/Acoustic Electromagnetic Transducers of Matrix Agile Laser Transmitters for Testing Metallurgical Objects - Google Patents

Abstract

A device (1) for non-destructive ultrasonic hybrid acoustic/laser electromagnetic transducers testing comprising a monolithic Rotating Optical Assembly (22) of matrix agile laser transmitters with guidance by multi-beam-laser jumps, for the control of metallurgical objects ( 5). It comprises: a Rotary Shaft (14); an Incoming Laser Source (16), producing an Incoming Laser Beam (18); a monolithic Rotating Optical Assembly (22), equipped with multiple Mirrors (M) which are rigidly connected to it in rotation according to perpendicular circles and around the same Rotating Shaft (14); a Drive Motor (24-a); and a set of directional Acoustic Electromagnetic Transducers (34). It makes it possible to periodically generate a plurality of Secondary Laser Beams (45) and Deviated Secondary Laser Beams (124) distributed over a Dotted Impact Line (70) and two parallel Dotted Impact Deflected Lines (130), impacting Rectangular Laser Impact Spots (47, 139, 142) of the Control Zone (3). It detects and qualifies Surface and Sub-Surface Discontinuities (12, 13) of metallurgical objects (5) with any orientations. A main industrial application is the continuous three-dimensional control of steel slabs during their continuous casting in the steelworks.

Description

Hybrid Ultrasonic Non-Destructive Test Device Acoustic/Laser Electromagnetic Transducers comprising a monolithic rotating optical assembly of matrix agile laser transmitters with laser multi-beam guidance for testing metallurgical objects

This invention relates generally to an ultrasonic non-destructive testing technology (CNDU), intended to equip a machine tool for metalworking. It implements a technique of work by laser beam and treatment by laser shock. Therefore, the invention belongs to the technical field of class B23K and its subclass 26, of the international patent classification.

1. une surveillance de la qualité de pièces métalliques, par focalisation de faisceau laser (B23K 26/02 et 26/03);
2. une focalisation automatique de faisceaux laser (B23K 26/04);
3. une mise en forme du faisceau laser, à l’aide de foyers multiples (B23K 26/06);
4. des moyens optiques de mise en forme du faisceau laser, de type lentilles et miroirs (B23K 26/064);
5. une division du faisceau laser en faisceaux multiples, avec des foyers multiples (B23K 26/067);
6. des moyens de détermination de la configuration du spot laser (B23K 26/073);
7. un mouvement relatif entre le faisceau laser et la pièce (B23K 26/08);
8. un système de balayage, comportant un mouvement relatif entre le faisceau laser et la tête du laser (B23K 26/082);
9. un traitement par chocs laser (B23K 26/356);
10. un dispositif formant une ligne pointillée d’impacts laser sur la pièce (B23K 26/359);
11. des équipements auxiliaires, et notamment des transducteurs électromagnétiques acoustiques de type TEMA (dits EMAT en anglais) (B23K 26/70).

The invention mainly implements a monolithic rotating optical assembly of TLAM type mirrors (designated by ABLAT in English), to perform agile guidance of outgoing secondary laser multibeams, from the same incoming laser beam, implementing:

1. monitoring the quality of metal parts, by laser beam focusing (B23K 26/02 and 26/03);
2. automatic focusing of laser beams (B23K 26/04);
3. shaping the laser beam, using multiple focal points (B23K 26/06);
4. optical means for shaping the laser beam, of the lens and mirror type (B23K 26/064);
5. dividing the laser beam into multiple beams, with multiple focal points (B23K 26/067);
6. means for determining the configuration of the laser spot (B23K 26/073);
7. relative movement between the laser beam and the work (B23K 26/08);
8. a scanning system, including relative movement between the laser beam and the laser head (B23K 26/082);
9. laser shock treatment (B23K 26/356);
10. a device forming a dotted line of laser impacts on the workpiece (B23K 26/359);
11. auxiliary equipment, and in particular acoustic electromagnetic transducers of the TEMA type (known as EMAT in English) (B23K 26/70).

1. fait de multiples miroirs rigidement liés, arrangés selon une hélicoïde à pas de vis cylindrique circulaire,
2. en rotation selon un cylindre autour d’un même arbre rotatif, et,
3. animé par un même moteur d’entrainement,
4. pour effectuer un guidage agile multi-faisceaux-laser.

The invention generally relates to a CNDU technology of hybrid TEMAs/Laser type, comprising a monolithic rotating optical TLAM assembly (designated by ABLAT), for the control of metallurgical objects,

1. made of multiple rigidly linked mirrors, arranged in a circular cylindrical screw-thread helicoid,
2. in rotation according to a cylinder around the same rotary shaft, and,
3. driven by the same drive motor,
4. to perform agile multi-beam-laser guidance.

1. une émission de vibrations mécaniques ultrasoniques par process par choc laser, à l’aide d’une multitude de faisceaux laser secondaires distants déviés impactant la pièce métallique; ce de manière agile par saut à partir d’un même faisceau laser entrant, et,
2. la réception et le monitorage des signaux-induits par les vibrations mécaniques ultrasoniques induites dans la pièce métallique, à l’aide d’ une multitude de transducteurs électromagnétiques acoustiques de type TEMA (dit EMAT en anglais) ou équivalents, fonctionnant en mode réception.

The technology of the invention also relates to such a hybrid TEMAs/Laser CNDU device of the TLAM type (designated by ABLAT in English) implementing a technique combining both:

1. an emission of ultrasonic mechanical vibrations per process by laser shock, using a multitude of deflected remote secondary laser beams impacting the metal part; this in an agile way by jumping from the same incoming laser beam, and,
2. the reception and monitoring of the signals induced by the ultrasonic mechanical vibrations induced in the metal part, using a multitude of acoustic electromagnetic transducers of the TEMA type (called EMAT in English) or equivalent, operating in reception mode.

The main application of the device of the invention is the quality control of the side faces of large metallurgical parts, in particular the upper and lower faces of steel slabs, and of the continuous casting of steel in a steelworks.

The detection and characterization of defects in metallurgical products is commonly performed by non-destructive ultrasonic inspection CNDU systems.

One of the CNDU techniques described by the prior art is the CCNDU technique (designated by CUNDT in English), implementing in particular a TEMA acoustic electromagnetic transducer (known as EMAT in English) and, based on a magnetic coupling mechanism. The sound waves are generated within the material, not by contact with the material surface of the tested products. TEMAs offer strong advantages over CCNDU piezoelectric transducers. A TEMA can generate, as a transmitter, and/or receive as a receiver, different modes of ultrasonic waves in conductive materials, without physical contact, and without using liquid couplant with the parts under test. Such non-contact and couplant-free features improve test reliability. Furthermore, the physical properties of the ultrasonic wave transmission path do not change due to the contact. Additionally, the tolerance specifications required for position and propulsion of metallurgical parts tested by TEMA probes are quite loose. This makes TEMAs transducers a particularly well-suited solution for industrial applications, such as those involving medium and high temperature inspection, and poor surface conditions of the metallurgical parts under test. A TEMA is known in the state of the art as being a low efficiency ultrasonic wave transmitter, but as being an efficient ultrasonic wave receiver.

A variant of the CCNDU technique, described by the prior art, is the TEMA/Laser hybrid technology. Ultrasonic generation is produced by one (or more) pulsed laser(s). And the detection of ultrasonic waves is performed by one (or more) TEMA acoustic electromagnetic transducer(s), which are combined into a hybrid TEMA/Laser ultrasonic technique, for the inspection of discontinuities in metallurgical products. The resulting hybrid TEMA/Laser technology is still technically non-contact. The TEMA is placed in close proximity to the surface of the product. The TEMA can be configured to operate at elevated temperatures. Prior art hybrid TEMA/Laser systems are a better combination for non-destructive ultrasonic testing of a metallurgical product without surface contact. One of the main advantages of this hybrid TEMA/Laser technology, besides being non-contact, is its ability to simultaneously detect surface defects (using Rayleigh waves) and subsurface defects. surface to depth (using longitudinal and transverse waves). The use of a laser emitter, instead of a TEMA emitter, makes it possible to generate different types of inclined ultrasonic waves, of higher frequency (10 MHz), and of greater intensity than that which can be wait with a TEMA transmitter. In addition, the laser impact of a laser emitter can generate ultrasonic waves at great depth and at a great distance from the surface of the material. While the efficiency of a TEMA emitter decreases considerably with the distance from the material surface and the distance from the discontinuities. Typically, 2-3mm is generally the maximum distance allowed to maintain the effectiveness of a TEMA transmitter.

According to CNDU prior art, ultrasound data of the topology of discontinuities in a product can be digitally processed and displayed in a number of different formats. The most common formats are called A-Scan, B-Scan and C-Scan; or their equivalent topological presentations. Each A-Scan, B-Scan and C-Scan presentation mode offers a different way to view and evaluate discontinuities on and/or within the material of the product being inspected. It is usual to digitize and/or display the results of a CNDU test successively in the three presentation forms.

According to the CNDU prior art, when a single ultrasonic receiver is positioned at a point on the surface of the product and is induced by an ultrasonic transmitter, the most basic presentation of ultrasonic-waveform data received, seen and provided by a single ultrasonic receiver, comes in the form of an A-scan waveform display received. In an A-Scan, the amplitude of the echoes and the transit time of the ultrasonic signal from the discontinuities, picked up by a TEMA, are plotted on a simple diagram. The vertical axis represents signal amplitude and the horizontal axis represents transit time. Sound energy from the ultrasonic transmitter is induced and propagated through the material as ultrasonic waves. When there is a discontinuity in the body of the product, part of the energy of a wave path is reflected by such a discontinuity reflector to the ultrasonic receiver. The A-Scan presentation displays the amount of ultrasound energy received as a function of transit time. The relative amount of energy received is plotted along the vertical axis. The elapsed transit time, which is related to the distance traveled through the material, is displayed along the horizontal axis. In the A-Scan presentation, the relative size of discontinuities can be estimated by comparing the amplitude of the signal obtained from an unknown discontinuity reflector to that of a known discontinuity reflector.

1. soit par un seul récepteur ultrasonique déplacé par étapes suivant une matrice linéaire réceptrice faite de points récepteurs successifs le long de la ligne de détection;
2. soit par une multitude de récepteurs ultrasoniques disposés de manière fixe dans les points récepteurs distants d’une matrice linéaire réceptrice disposée le long de la ligne de détection;
3. soit par un seul récepteur ultrasonique fixe induit par une multitude d'émetteurs ultrasonores disposés de manière fixe en des points émetteurs distants, disposés le long d’une ligne d’impulsion d’une matrice linéaire émettrice.

According to the CNDU prior art, when implementing a line scan of an object, along a detection line on the surface of the object, belonging to a scan plane crossing it vertically, a B-Scan shows a cross-sectional digitized view of the product according to the scan plane crossing the detection line. A B-Scan combines the multiple A-Scans data provided,

1. either by a single ultrasonic receiver moved in stages along a linear receiver matrix made up of successive receiver points along the detection line;
2. either by a multitude of ultrasonic receivers arranged in a fixed manner in the remote receiving points of a linear receiving matrix arranged along the detection line;
3. or by a single fixed ultrasonic receiver induced by a multitude of ultrasonic emitters arranged in a fixed manner at distant emitting points, arranged along a pulse line of a linear emitting matrix.

In a B-Scan, the depth of a discontinuity reflector is displayed along the vertical axis. From a B-Scan, the depth of the discontinuity reflectors and their approximate linear dimensions in the direction of the scan line can be determined.

C-Scan presentation is a type of presentation that is possible when a multitude of two-dimensional B-Scans are made along successive and separate parallel detection (scanning) lines, positioned perpendicular to an axis of the product. A C-Scan is a plan-like view of the three-dimensional location and size of discontinuities. The C-Scan image represents a top view of the product parallel to the scan pattern of multiple detection lines. The C-Scan presentation provides a 3D view of the characteristics of product discontinuities that reflect and scatter sound waves off the surface and within the product.

According to the CNDU prior art, it is known to implement an ultrasonic laser pulse array (LEA) on a product, from several laser beams. It is also known to implement a matrix of ultrasonic TEMA (ERA) receivers arranged on the product.

It is also known from the CNDU prior art to combine ultrasonic laser transmitters and TEMAs receivers, in a dual-array TEMAs/Laser-Pulses hybrid ultrasonic CNDU device, including an ultrasonic laser pulse array (LEA) , and an ultrasonic TEMA (ERA) receptor array.

It is known from the prior art to use a diffractive beam splitter (LBS) to split (in parallel) an incoming pulsed laser beam and its power into a packet of n outgoing pulsed secondary laser beams, focused in parallel on n distant pulse points of an ultrasonic laser pulse array (LEA), according to a so-called “Beam Splitting” technique. Due to parallel splitting, the energy of each pulsed outgoing laser beam is divided by more than n.

An example of this “Beam Splitting” technique is described in US Patent 7,629,555 B2 in the name of Gross et al. This technique is unsuitable for industrial applications for controlling large metallurgical parts, which require a laser pulse array (LEA) made of high-intensity outgoing laser beams.

It is also known from the prior art to use a Continuous Beam Scanner (LSS), to continuously move a pulsed incoming laser beam into a continuous slice of pulsed outgoing laser beams, focused in a continuously moving, but not successively point-like, manner. along a line of focus through possibly n pulse points of an ultrasonic laser pulse array (LEA). This so-called "Beam Steering" technology generally refers to any continuously variable optical element, including for example moving lenses, variable prisms, variable focal length lenses, deformable mirrors, oscillating mirrors, spatial phase modulators, etc The most common way to continuously redirect a pulsed incoming laser beam is to reflect it off mirrors or diffract it by holographic gratings mounted on mechanical scanners, such as rotating prisms, oscillating mirror scanners. The classic "Beam Steering" technique is not suitable for efficient industrial CNDU applications. Because the position and therefore the energy of the pulsed outgoing laser beams is diffused in continuous motion in the direction of the material; and unfocused and unfocused at distant discrete pulse points.

An example of this “Beam Steering” technique is described in US Patent 4,838,631 in the name of Chande et al. The device described uses a galvanometric mirror to continuously redirect the incoming laser beam in the direction of several optical fibers. The fact of using a galvanometric mirror, which by nature is not rigidly fixed, but oscillates, makes the device very fragile to vibrations. This technology cannot be used effectively in very harsh and high-vibration environments, such as the metallurgical industry. Furthermore, the “Beam Steering” techniques, and in particular those using a galvanometric mirror, can only produce small angular variations of the incoming laser beam. As a result, the devices of this technique require a large footprint in the direction perpendicular to the impact plane.

Agile Matrix Laser Transmitters TLAM (designated by ABLAT in English) are known from the prior art. Agile focusing by ABLAT of an incoming laser beam consists of diffracting it in a discontinuous sequential manner and by jumps into a multitude of successive angularly distant outgoing laser beams, in the direction of n scattered pulse points distant from a laser pulse matrix (LEA) ultrasonic; rather than directing them to a continuous sweep line. TLAMs (designated by ABLATs in English) are generally used by the prior art in fields of very high technology, in laser communications, target acquisition and tracking, laser microscopy and interferometry. The main areas of application are: that of laser radars, which require the ability to quickly point to a large number of widely spaced objects; target tracking and discrimination; that of sensors for surveillance, and that of tracking space objects. They are not currently used or known from the prior art for metallurgical industry quality control CNDU applications.

The prior art conceptually closest to the invention is described in US Patent 5,948,291 in the name of Neylan et al. The device described comprises an incoming laser beam, and a multitude of n rotating reflector discs, independent of each other, each comprising on their periphery, either a totally reflective fraction (mirror), or a totally transmissive and therefore non-reflective fraction, or a partially transmissive fraction (partial mirror).

The n independent reflector discs of the device are each fixed on n different uncoupled rotary axes. The incoming laser beam is aligned on the base and at the periphery of the various rotating reflector discs. The device further comprises a device for selective control of the n different motors, in order to be able to produce, by a differential rotation of the n uncoupled reflector discs, different energy amplitude scenarios of the deflected outgoing laser beams impacting a dotted line of dots fixed impacts. The device comprises lenses for focusing the outgoing laser beams. But, it should be noted that the device described, if it comprises n reflector discs comprising n fractions of rotating mirrors, then it necessarily comprises n different rotary axes of these n independent rotating reflector discs; and n independent means for rotating these n rotary axes; i.e. either n different motors, or n mechanical rotary coupling devices of the gear type or equivalent.

This prior art device described is not of the optical-electromagnetic-acoustic CNDU hybrid TEMAs/Laser type. It does not include a sensor assembly, made up of acoustic electromagnetic transducers of the TEMA type or equivalent. It is not intended for quality control of metallurgical parts. And it does not describe the technical means of such a technical result by ABLAT method.

1. Son assemblage optique rotatif, incluant les n miroirs formés des fractions totalement ou partiellement réfléchissantes de ses n disques réflecteurs indépendants non accouplés, est structurellement non monolithique. Il est constitué de pièces optiques/mécaniques indépendantes, qui ne sont pas toutes rigidement mécaniquement liées, et qui ne sont pas en position fixe les unes par rapport aux autres. En particulier, les n disques réflecteurs et leurs n axes rotatifs sont en rotation l’un par rapport à l’autre, et donc sont non fixes l’un par rapport à l’autre. L’assemblage optique rotatif est donc à géométrie déformée au cours de la rotation. Son assemblage optique rotatif, constitué des n disques réflecteurs indépendants en rotation, n’est pas fixé rigidement sur un même arbre rotatif.
2. Les n miroirs et leurs n point de réflexion associés ne sont pas en position fixe par rapport au même axe de rotation. Et, ils ne sont mis en rotation synchronisée par le même moteur d’entraînement.
3. Les n disques réflecteurs rotatifs sont obligatoirement en position rotative inclinée par rapport à l’axe de rotation globale. De ce fait, pendant la mise en rotation de l’ assemblage optique rotatif, les distances de réflexion rotatives des n points de réflexion des n miroirs, perpendiculairement et vis-à-vis de l’axe de rotation principal, sont toutes continument variables.
4. Chacun des n points de réflexion des n miroirs parcourt un cercle de rotation, centré sur l’axe de rotation principal. Ce cercle de rotation n’est pas perpendiculaire, mais continument incliné de sensiblement 45° vis-à-vis de l’axe de rotation principal.
5. La projection de ce cercle de rotation, parallèlement à un plan de projection parallèle à l’ axe de rotation principal et passant par son centre de rotation, est formée d’une ellipse et non pas d’un segment.
6. La projection de ce cercle de rotation, parallèlement à un plan de rotation perpendiculaire à l’ axe de rotation principal et passant par son centre de rotation, est également formée d’une ellipse et non d’un cercle.
7. Le cylindre de réflexion virtuel entourant les n points de réflexion des n disques réflecteurs inclinés, qui lui sont liés, est déformé et n’a pas un rayon de cylindre constant au cours de la rotation.
8. Les n points de réflexion des n miroirs indépendants de ces n disques réflecteurs ne sont pas longitudinalement fixes, au cours du mouvement rotatif, mais ils sont en mouvement longitudinal alternatif vis-à-vis de l’axe principal de rotation et de l’axe du faisceau laser principal, alternativement en avant puis en arrière.
9. La ligne hélicoïdale pointillée rotative joignant les n points de réflexion des n miroirs, est à enroulement elliptique déformé au cours de la rotation et non à enroulement circulaire fixe. Elle n’a pas un de pas de vis circulaire.

This device of the prior art described can, in certain configurations described, operate in an agile manner like a TLAM (designated by ABLAT in English). But in such an ABLAT type configuration:

1. Its rotating optical assembly, including the n mirrors formed from the fully or partially reflecting portions of its n independent uncoupled reflector discs, is structurally non-monolithic. It is made up of independent optical/mechanical parts, which are not all rigidly mechanically linked, and which are not in a fixed position with respect to each other. In particular, the n reflector discs and their n rotary axes rotate relative to each other, and therefore are not fixed relative to each other. The rotating optical assembly therefore has a deformed geometry during the rotation. Its rotating optical assembly, consisting of n independent reflector discs in rotation, is not fixed rigidly to the same rotating shaft.
2. The n mirrors and their n associated reflection points are not in a fixed position with respect to the same axis of rotation. And, they are only rotated in sync by the same drive motor.
3. The n rotating reflector discs are necessarily in an inclined rotary position with respect to the overall axis of rotation. Therefore, during the rotation of the rotating optical assembly, the rotational reflection distances of the n reflection points of the n mirrors, perpendicular to and with respect to the main axis of rotation, are all continuously variable.
4. Each of the n reflection points of the n mirrors traverses a circle of rotation, centered on the main axis of rotation. This circle of rotation is not perpendicular, but continuously inclined by substantially 45° with respect to the main axis of rotation.
5. The projection of this circle of rotation, parallel to a projection plane parallel to the main axis of rotation and passing through its center of rotation, is formed by an ellipse and not by a segment.
6. The projection of this circle of rotation, parallel to a plane of rotation perpendicular to the main axis of rotation and passing through its center of rotation, is also formed by an ellipse and not by a circle.
7. The virtual reflection cylinder surrounding the n reflection points of the n inclined reflector discs, which are connected to it, is deformed and does not have a constant cylinder radius during rotation.
8. The n points of reflection of the n independent mirrors of these n reflector discs are not longitudinally fixed, during the rotary movement, but they are in alternating longitudinal movement with respect to the main axis of rotation and the axis of the main laser beam, alternately forwards then backwards.
9. The rotating dotted helical line joining the n reflection points of the n mirrors is of elliptical winding deformed during rotation and not of fixed circular winding. It does not have a circular screw thread.

The main defect of this device of the prior art, when it is used in TLAM mode (designated by ABLAT in English), is that it requires n rotary shafts and n independent means for rotating n these rotary shafts, motor type or equivalent, to deflect the incoming laser beam into n outgoing laser beams impacting n laser impact points. This induces construction costs, an increase in volume and weight, sensitivity to vibrations, fragility, and risks of breakdowns, substantially proportional to the number of rotating shafts. In addition, this leads to an increase in the vertical size of the device which prevents it from being used in industrial applications with reduced available space.

Technical problem

1. Les dispositifs CNDU hybride TEMAs/Laser de type séparation de faisceaux (désignés par «Beam Splitting» en anglais) sont inefficaces. Car ils entrainent une division de la puissance laser entrante proportionnelle au nombre de faisceaux sortant secondaires impactant des points d’impact laser. De ce fait ils diminuent le ratio signal-bruit et affaiblissent proportionnellement la résolution du contrôle CNDU. Ces dispositifs sont de ce fait inadapté dans des applications CNDU industrielles, tel que le contrôle de pièces métallurgiques, qui nécessitent des chocs laser de haute énergie.
2. Les dispositifs CNDU hybride TEMAs/Laser non agiles de type à déplacement continu de faisceaux (désignés par «Beam Steering» en anglais), sont très fragile et sensibles aux vibrations. Ils nécessitent un grand encombrement dans la direction perpendiculaire au plan d’impact. Ces dispositifs sont de ce fait inutilisables dans des applications CNDU industrielles telles que le contrôle de la face inférieure d’une coulée d’acier dans une aciérie, ou les vibrations sont importantes, et où la place verticale disponible est réduite.
3. Les dispositifs CNDU hybride TEMAs/Laser, de type agile et Transmetteurs Laser Agiles Matriciels (TLAM) (désignés par « Agile-Beam Laser Array Transmitters » ou ABLAT en anglais), de l’art antérieur sont à assemblage optique rotatif non monolithique. Ils nécessitent un grand nombre de pièces optiques/mécaniques non liées l’une à l’autre, et en mouvements de rotation indépendants. Ils nécessitent un grand nombre d’arbres rotatifs, et un grand nombre de moyens indépendants de mise en rotation de ces arbres rotatifs, de type moteur ou équivalent, qui sont généralement proportionnels au nombre de points d’impact laser. Ils sont de ce fait résonnant et sensibles aux vibrations. Ils sont couteux. Leur prix est sensiblement proportionnel au nombre de points d’impact laser. Du fait de leur nombre important de moteurs et d’arbres rotatifs à axes non colinéaires au faisceau laser entrant, ils sont encombrants dans le sens vertical au plan d’impact Laser, c’est-à-dire perpendiculairement à la zone de contrôle d’une pièce métallique. En outre leur assemblage optique rotatif non monolithique entraine des risques de démantèlement à haute vitesse de rotation; et donc, des risques de sécurité de non-protection contre les faisceaux laser à haute énergie qui pourraient être déviés accidentellement de leur trajectoire. En sorte que ces dispositifs ne sont ni techniquement, ni économiquement, ni en matière de sécurité, adaptés au contrôle CNDU de pièces métallurgiques dans un environnement industriel difficile. Ils sont en outre inutilisables pour des application industrielles à place disponible réduite, telles que le contrôle de la face inférieure d’une coulée d’acier dans une aciérie, ou la place verticale inférieure disponible entre les rouleaux d’appuis de la coulée en continu est très réduite.

It appears from the analysis of the prior art, that due to the above limitations, hybrid Laser-TEMA CNDU devices suffer in particular from the following disadvantages for CNDU quality control A-Scanning and B-Scanning: metallurgical objects, which the invention aims to solve:

1. TEMAs/Laser hybrid CNDU devices of the beam splitting type (designated by "Beam Splitting" in English) are inefficient. Because they lead to a division of the incoming laser power proportional to the number of secondary outgoing beams impacting laser impact points. As a result, they decrease the signal-to-noise ratio and proportionally weaken the resolution of the CNDU control. These devices are therefore unsuitable for industrial CNDU applications, such as the control of metallurgical parts, which require high-energy laser shocks.
2. The non-agile hybrid TEMAs/Laser CNDU devices of the continuous beam displacement type (designated by "Beam Steering" in English), are very fragile and sensitive to vibrations. They require a large footprint in the direction perpendicular to the plane of impact. These devices are therefore unusable in industrial CNDU applications such as the control of the lower face of a steel casting in a steelworks, where the vibrations are significant, and where the vertical space available is reduced.
3. The TEMAs/Laser hybrid CNDU devices, of the agile type and Agile Matrix Laser Transmitters (TLAM) (designated as “Agile-Beam Laser Array Transmitters” or ABLAT), of the prior art are of non-monolithic rotating optical assembly. They require a large number of optical/mechanical parts not linked to each other, and in independent rotational movements. They require a large number of rotary shafts, and a large number of independent means for rotating these rotary shafts, of the motor or equivalent type, which are generally proportional to the number of laser impact points. They are therefore resonant and sensitive to vibrations. They are expensive. Their price is substantially proportional to the number of laser impact points. Due to their large number of motors and rotating shafts with non-collinear axes to the incoming laser beam, they are cumbersome in the vertical direction to the laser impact plane, that is to say perpendicular to the control zone of a metal part. In addition, their non-monolithic rotary optical assembly entails risks of dismantling at high rotation speed; and therefore, security risks of non-protection against high energy laser beams which could be accidentally deviated from their trajectory. As a result, these devices are neither technically nor economically nor in terms of safety suitable for the CNDU control of metallurgical parts in a harsh industrial environment. They are also unusable for industrial applications with reduced available space, such as the control of the underside of a steel casting in a steel mill, or the lower vertical space available between the support rolls of continuous casting. is very reduced.

1. effectuant la scannographie en continu de pièces métalliques en milieu hostile, à place disponible réduite et à haut niveau de vibrations; et,
2. notamment, effectuant le contrôle qualité de brames d’acier de grandes sections, en vue de la détection et la caractérisation objective de leurs discontinuités de surface et de sous surface, lors de (ou après) leur coulée en continu en aciéries; ce,
3. avec un seul assemblage optique rotatif monolithique de pièces mécaniques et/ou optiques toutes rigidement liées entre elle, en rotation autour d’un seul axe de rotation, et,
4. dont l’assemblage optique rotatif est activé par un seul moteur d’entraînement;
5. dont les points d’impact des faisceaux laser secondaires sont alignés sur plusieurs lignes pointillées d'impacts distantes;
6. dont les spots d’impacts laser des faisceaux laser secondaires sont fins et rectangulaires; et orientés selon différents axes d’orientation, notamment perpendiculaires; et,
7. dont les transducteurs électromagnétiques acoustiques TEMA ont des orientations directionnelles privilégiées de capture des signaux induits ultrasoniques générés par les discontinuités, qui sont organisés géométriquement vis à vis de spots d’impacts laser rectangulaires orientés, pour assurer la détection et la qualification de discontinuités d’une pièce métallique, ayant des orientations principales quelconques de défauts, aussi bien longitudinales que transversales.

The prior art does not offer any effective, safe and economical technical solution for configuring a CNDU device to equip a machine tool:

1. carrying out continuous scanning of metal parts in a hostile environment, with reduced available space and a high level of vibration; And,
2. in particular, carrying out the quality control of steel slabs of large sections, with a view to the detection and objective characterization of their surface and subsurface discontinuities, during (or after) their continuous casting in steelworks; This,
3. with a single monolithic rotating optical assembly of mechanical and/or optical parts all rigidly linked together, rotating around a single axis of rotation, and,
4. whose rotating optical assembly is driven by a single drive motor;
5. of which the points of impact of the secondary laser beams are aligned on several dotted lines of distant impacts;
6. whose laser impact spots of the secondary laser beams are thin and rectangular; and oriented along different orientation axes, in particular perpendicular; And,
7. whose TEMA acoustic electromagnetic transducers have preferred directional orientations for capturing the ultrasonic induced signals generated by the discontinuities, which are geometrically organized with respect to oriented rectangular laser impact spots, to ensure the detection and qualification of discontinuities of a metal part, having any principal orientations of defects, both longitudinal and transverse.

Briefly, an object of this invention is to provide a new hybrid TEMAs/Laser optical-electromagnetic-acoustic CNDU device, comprising a monolithic Rotating Optical Assembly of the TLAM type (designated by ABLAT in English), with agile multi-beam-laser guidance , to equip a Machine Tool carrying out quality control of metalworking, on a Control Zone of the Surface of a Metal Part.

1. d’un Process par Chocs effectué par faisceaux laser, générant des Chocs Laser sur la Zone De Contrôle, induisant des Vibrations Mécaniques dans le Corps de la Pièce Métallique, et,
2. d’un Monitorage, par des Transducteurs Électromagnétique Acoustique TEMA, des Signaux Induits ultrasoniques générés par l'interaction des Vibrations Mécaniques avec les Discontinuités De Surface et les Discontinuités De Sous-Surface dans le Corps de la Pièce Métallique, qui doivent être caractérisées.

The Device according to the invention is of the type which operates by a combination:

1. a Process by Shocks carried out by laser beams, generating Laser Shocks on the Control Zone, inducing Mechanical Vibrations in the Body of the Metal Part, and,
2. Monitoring, by TEMA Acoustic Electromagnetic Transducers, of the Induced Ultrasonic Signals generated by the interaction of Mechanical Vibrations with Surface Discontinuities and Sub-Surface Discontinuities in the Body of the Metallic Part, which must be characterized.

1. un Arbre Rotatif;
2. une Source-Laser-Entrante;
3. un Assemblage-Optique-Rotatif;
4. des Moyens De Rotation;
5. un Ensemble Réflecteur monolithique; et,
6. un Ensemble Capteur.

The invention relates to a hybrid TEMAs/Laser CNDU device of the specific type described below. The Device includes:

1. a Rotary Shaft;
2. an Incoming-Laser-Source;
3. a Rotary-Optical-Assembly;
4. Rotating Means;
5. a monolithic Reflector Assembly; And,
6. a Sensor Assembly.

The Rotary Shaft is able to rotate around the Axis Of Rotation. The Incoming Laser Source is equipped with Optical Guide Means, configured to produce an Incoming Laser Beam with a certain Incoming Laser Power, directed along an Incoming Beam Axis parallel to the Rotation Axis, at a certain Distance From Rotation Axis Beam. The Rotating Optical Assembly is configured to rotate around the Axis of Rotation. The Rotating Means includes a Drive Motor, connected to the Rotating Shaft. It is configured to induce its rotation around the Axis Of Rotation, with a continuous Direction Of Rotation, either continuous clockwise or continuous anti-clockwise. The Reflector Assembly is part of the Rotating Optical Assembly. It is composed of a plurality (of at least two) Mirrors acting as an Optical Barrier.

1. le Miroir intercepte l’Axe De Faisceau Entrant, et,
2. le Miroir présente un Point De Réflexion (i) positionné à une certaine Distance De Réflexion rotative perpendiculaire de l'Axe De Rotation, (ii) pour réfléchir le Faisceau Laser Entrant impacté sur ce Miroir (M), (iii) avec un changement de Direction Angulaire De Faisceau, et (iv) avec une Efficacité De Réflexion de l'énergie du Faisceau Laser Entrant sensiblement égale à cent pour cent.

Each of the Mirrors is configured so that, in certain rotary positions of the Rotary-Optical-Assembly:

1. the Mirror intercepts the Incoming Beam Axis, and,
2. the Mirror has a Reflection Point (i) positioned at a certain Rotating Reflection Distance perpendicular to the Rotation Axis, (ii) to reflect the Incoming Laser Beam impacted on this Mirror (M), (iii) with a change of Angular Beam Direction, and (iv) with an Incoming Laser Beam Energy Reflection Efficiency substantially equal to one hundred percent.

The Sensor Assembly is composed of a plurality of (at least two) Acoustic Electromagnetic Transducers of the TEMA type. Their Active Electromagnetic Probe faces the Control Zone and is substantially centered on a Control Zone Detection Point. Each Active Electromagnetic Probe is configured to generate an A-Scan Signal for detecting the position of the Defects versus time/distance, acquired from the Ultrasonic Induced Signals in the vicinity of its Detection Point.

1. Le Faisceau Laser Entrant impacte successivement un Point De Réflexion associé et appartenant à un de ses Miroirs distants.
2. Chacun des Points De Réflexion des Miroirs, parcourt un Cercle De-Rotation, d’un certain Rayon De Rotation, centré sur un Centre De Rotation fixe sur l’Axe De Rotation;
3. Les différents Miroirs redirigent de manière agile, successivement et de manière discontinue le Faisceau Laser Entrant selon une Collection Faisceaux Secondaires, faite d’un fagot de Faisceaux Laser Secondaires distants, issus d’une multitude de changements successifs et discontinus des Directions Angulaires De Faisceau du Faisceau Laser Entrant, par réflexion sur la succession des Miroirs distants et en rotation.
4. L’ Assemblage Optique Rotatif et ses Miroirs sont configurés géométriquement de telle sorte les Faisceaux Laser Secondaires générés successivement impactent un Ensemble Impacts fait d’une multitude de Points-D’Impact distants, situés
   1. soit sur le Plan D’Impact faisant face à l’Assemblage Optique Rotatif, situé sur la Surface de la Zone De-Contrôle, et à proximité d'un Point De Détection d'un Transducteur Électromagnétique Acoustique TEMA, ou,
   2. soit sur un Miroir Auxiliaire.

The Device of the invention is of the type comprising a Rotating Optical Assembly geometrically configured such that, when the Drive Motor is activated:

1. The Incoming Laser Beam successively impacts an associated Reflection Point belonging to one of its distant Mirrors.
2. Each of the Points of Reflection of the Mirrors, traverses a Circle of-Rotation, of a certain Radius of Rotation, centered on a Center of Rotation fixed on the Axis of Rotation;
3. The various Mirrors redirect the Incoming Laser Beam in an agile, successive and discontinuous manner according to a Collection of Secondary Beams, made up of a bundle of distant Secondary Laser Beams, resulting from a multitude of successive and discontinuous changes in the Angular Directions of the Beam of the Incoming Laser Beam, by reflection on the succession of distant and rotating Mirrors.
4. The Rotating Optical Assembly and its Mirrors are geometrically configured such that successively generated Secondary Laser Beams impact an Impact Set made up of a multitude of distant Impact Points, located
   1. either on the Impact Plane facing the Rotating Optical Assembly, located on the Control Zone Surface, and close to a Detection Point of a TEMA Acoustic Electromagnetic Transducer, or,
   2. or on an Auxiliary Mirror.

1. Son Assemblage Optique Rotatif, incluant ses Miroirs, leurs pièces mécaniques de connexion et ses Point De Réflexion associés, en rotation,
   1. est monolithique, c’est-à-dire constitué de pièces mécaniques et/ou optiques toutes rigidement mécaniquement liées entre elles et en position fixe non modifiable les unes par rapport aux autres;
   2. est fixé rigidement par des Moyens De Fixation sur le même Arbre Rotatif; et
   3. à une géométrie rigide indéformable au cours de sa rotation.
2. Les Miroirs de l’ Ensemble Réflecteur et leurs Points De Réflexion associés, sont en position fixe par rapport au même Axe De Rotation, et sont mis en rotation synchronisée par le même Moteur D’Entraînement.
3. Pendant la mise en rotation de l’Assemblage Optique Rotatif par le Moteur-D’Entraînement :
   1. Les Distances De Réflexion rotatives des Points De Réflexion de tous les Miroirs, perpendiculairement et vis-à-vis de l’ Axe De Rotation, sont toutes continument égales entre elles et sensiblement égales à la Distance De Faisceau.
   2. Chacun des Points De Réflexion de tous les Miroirs, parcourt un Cercle De Rotation, centré sur l’Axe De Rotation,
      • chacun continument perpendiculaire à l’Axe-De-Rotation, et,
      • chacun ayant un Rayon De Rotation, constitué par sa Distance De-Réflexion, continument égal à la Distance De Faisceau.
   3. Chacun des Cercles De Rotation :
      • présente une projection, parallèlement à un plan de projection parallèle à l’ Axe De Rotation et passant par son Centre De Rotation, formée d’un Segment De Mouvement Transversal, perpendiculaire à l’ Axe De-Rotation et centré sur son Centre De Rotation; et,
      • présente une projection, parallèlement à un plan de rotation perpendiculaire à l’ Axe De Rotation et passant par son Centre De Rotation, formée d’un Cercle De Mouvement Projeté Planaire, confondu avec le Cercle De Rotation, et ayant un Rayon De Rotation Projetée, continument égal à la Distance De Faisceau.

The Device of the invention is characterized by the differentiating technical combination of the following combined technical characteristics:

1. Its Rotating Optical Assembly, including its Mirrors, their mechanical connection parts and its associated Reflection Points, in rotation,
   1. is monolithic, that is to say made up of mechanical and/or optical parts all rigidly mechanically linked together and in a fixed position which cannot be modified with respect to each other;
   2. is fixed rigidly by Fixing Means on the same Rotary Shaft; And
   3. to a rigid geometry that does not deform during its rotation.
2. The Mirrors of the Reflector Assembly and their associated Reflection Points are in a fixed position with respect to the same Axis Of Rotation, and are rotated synchronized by the same Drive Motor.
3. While the Rotating Optical Assembly is being rotated by the Drive-Motor:
   1. The Rotational Reflection Distances of the Reflection Points of all the Mirrors, perpendicular to and relative to the Rotation Axis, are all continuously equal to each other and substantially equal to the Beam Distance.
   2. Each of the Points of Reflection of all the Mirrors, traverses a Circle of Rotation, centered on the Axis of Rotation,
      • each continuously perpendicular to the Axis-Of-Rotation, and,
      • each having a Rotation Radius, consisting of its De-Reflection Distance, continuously equal to the Beam Distance.
   3. Each of the Rotation Circles:
      • presents a projection, parallel to a projection plane parallel to the Axis Of Rotation and passing through its Center Of Rotation, formed by a Transverse Motion Segment, perpendicular to the Axis Of-Rotation and centered on its Center Of Rotation; And,
      • presents a projection, parallel to a plane of rotation perpendicular to the Axis Of Rotation and passing through its Center Of Rotation, formed by a Planar Projected Circle Of Motion, merged with the Circle Of Rotation, and having a Radius Of Projected Rotation, continuously equal to Beam Distance.

These and other features, aspects and advantages of the present invention will be better understood when the following detailed description is read with reference to the accompanying drawings, which illustrate the invention; in which identical characters represent identical parts throughout the drawings.

is a front view of the Device of the invention, in its schematic form.

is a perspective view of the Device of the invention, in its schematic form.

is a perspective view of the right part of the Device of the invention, in its schematic form.

is a perspective view of the central part of the Device of the invention, in its schematic form.

is a partial perspective view of the Device of the invention, in its schematic form, on which appear the circles of rotation, the virtual cylinder of reflection and the rotating helical line, on which the rotating mirrors are fixed.

is a front view of the Device of the invention, in its schematic form, on which appear the circles of rotation, the virtual cylinder of reflection and the rotating helical line, on which the rotating mirrors are fixed.

is a partial perspective view of the Device of the invention, in its schematic form, on which appear a detail of the virtual reflection cylinder and of the rotating helical line, on which the rotating mirrors are fixed in rotation.

is a partial front view of the Device of the invention, showing a detail of the virtual reflection cylinder and of the rotating helical line, on which appears the angular inclination of the rotating mirrors.

is a left view of the Device of the invention, in its schematic form.

is a simplified perspective view of the Device of the invention, in a configuration including a monolithic assembly of rotating cylindrical discs on which its rotating mirrors are fixed.

is a simplified front view of the Device of the invention, in a configuration including a monolithic assembly of rotating cylindrical discs on which its rotating mirrors are fixed.

is a partial perspective view of the Device of the invention, showing a detail of a configuration including a monolithic assembly of rotating cylindrical discs on which its rotating mirrors are fixed.

is partial magnified perspective view of the Device of the invention, or appears a detail of a configuration including a monolithic assembly of rotating cylindrical discs on which are fixed its rotating mirrors, and of their geometrical configurations.

is a perspective view of the Device of the invention, showing a configuration including a first stiffening assembly, made of upstream hollow rigid tubes, arranged in a stiffening cylinder.

is a perspective view of the Device of the invention, where a configuration appears including a first stiffening assembly, made of upstream hollow rigid tubes, arranged in a stiffening cylinder, fitted to the periphery of a monolithic assembly of rotating cylindrical discs, on which are fixed its rotating mirrors.

is a partial perspective view of the Device of the invention, or appears an enlarged detail of a configuration including a first stiffening assembly made of upstream hollow rigid tubes, arranged in a stiffening cylinder, nested at the periphery of a monolithic assembly rotating cylindrical discs on which its rotating mirrors are fixed.

is a perspective view of the Device of the invention, or appears a configuration including a second stiffening assembly, made of hollow downstream rigid tubes, arranged in a stiffening cylinder.

is a perspective view of the Device of the invention, where a configuration appears including a first stiffening assembly made of upstream rigid hollow tubes, and a second stiffening assembly made of downstream hollow rigid tubes, both arranged according to a stiffening cylinder and nested at the periphery of a monolithic assembly of rotating cylindrical discs on which are fixed its rotating mirrors.

is an enlarged partial perspective view of a detail of the configuration shown , where appears the relative positioning of the first and second stiffening assemblies vis-à-vis the rotating mirrors.

is a perspective view of the Device of the invention, showing a configuration including a focusing assembly made of focusing lenses.

is a partial perspective view of the Device of the Invention, showing a configuration including a focusing assembly made of cylindrical focusing lenses.

is a perspective view of the Device of the Invention, showing a configuration including a focusing assembly made of cylindrical focusing lenses, and an auxiliary reflector assembly.

is an enlarged partial perspective view of a detail of the auxiliary reflector assembly of the device configuration shown .

is a partial perspective view of the Device of the Invention, showing a configuration including a focusing assembly made of cylindrical focusing lenses, and an auxiliary reflector assembly, showing the geometric configuration of the secondary and secondary deflected laser beams generated.

is a perspective view of the Device of the invention, showing a configuration including a focusing assembly made of cylindrical focusing lenses, and an auxiliary reflector assembly, showing the geometric configuration of the generated secondary and secondary deflected laser beams, impacting 3 dotted lines parallels of laser impacts.

is a perspective view of the Device of the Invention, showing a configuration including a focusing assembly made of cylindrical focusing lenses, and an auxiliary reflector assembly, showing the geometric configuration of the secondary and deflected secondary beams generated, impacting 3 parallel dotted lines longitudinal and transverse rectangular laser impacts.

is a perspective view of the Device of the invention, showing a configuration including a focusing assembly made of cylindrical focusing lenses, and an auxiliary reflector assembly, showing the geometric configuration of the generated secondary and secondary deflected laser beams, impacting 3 dotted lines parallels of longitudinal and transverse rectangular laser impacts, and the optimal geometric configuration of directional TEMAs to detect longitudinal and transverse defects.

is seen in partial perspective of the Device of the invention, where appears a configuration including means for managing the angular position of the rotary mirrors.

is an overall perspective view of the Device of the invention.

is an overall perspective view of a Machine Tool equipped with two Devices of the invention, for carrying out quality control of the upper and lower face of steel slabs, during or after their continuous casting.

The invention offers valuable industrial advantages and applications in the metallurgical industry, and in all fields of engineering and mechanical construction.

The invention offers industrial applications for automated non-destructive testing and 2D and/or 3D ultrasonic scanning of large metallurgical objects, in particular for continuous 3D scanning and characterization of surface and/or subsurface discontinuities of these large metal objects. The invention thus improves the quality control of metal construction parts.

The preferred industrial applications of the invention relate to B-scannography and/or C-scannography and/or continuous high-throughput 3D CND imaging of surface and internal discontinuities, in the production of wide and thick metallurgical structures and /or industrial components made of a conductive material such as steel or aluminum.

A first main industrial application of the invention is that of the continuous 3D CND control of steel-slabs during their continuous casting, in the severe industrial environment and at high temperature (above 1000° C.) of a steelworks.

A second main industrial application of the invention is the 3D CND generation of the topological parameters of steel-slab discontinuities during their continuous casting, with a view to their use for the manual or automatic optimal adjustment of the equipment parameters. dynamic reduction (known as “Dynamic Soft Reduction” or DSR) of the continuous casting line of a steelworks.

Claims (27)

A Device (1) for non-destructive hybrid ultrasonic testing Electromagnetic Acoustic/Laser Transducers comprising a Monolithic Rotating Optical Assembly (22) of matrix agile laser transmitters with guidance by jumps of laser multibeams for the control of metallurgical objects, to equip a Machine - Tool (2) carrying out a quality control of the treatment of metals, on a Control Zone (3) of the Surface (4) of a Metal Part (5), by a combination: i) of a Process By Shocks ( PC) performed by laser beams, generating Laser Shocks (7) on the Control Zone (3), inducing Mechanical Vibrations (8) in the Body (9) of the Metal Part (5), and, ii) Monitoring (MO), by TEMA Acoustic Electromagnetic Transducers (34), ultrasonic Induced Signals (11) generated by the interaction of Mechanical Vibrations (8) with Surface Discontinuities (12) and Subsurface Discontinuities (13 ) in the Body (9) of the Metal Part (5) which must be characterized;
This Device (1) comprising:

1. a Rotary Shaft (14), capable of rotating around an Axis Of Rotation (15);
2. an Incoming Laser Source (16), equipped with Optical Guide Means (17), configured to produce an Incoming Laser Beam (18), with a certain Incoming Laser Power (IP), directed along an Incoming Beam Axis ( 20) parallel to the Axis Of Rotation (15), this at a certain Beam Distance (21) from the Axis Of Rotation (15);
3. a Rotating Optical Assembly (22) configured to rotate about the Axis Of Rotation (15);
4. Rotation Means (24) of the Rotating Optical Assembly (22),
   1. comprising a Drive Motor (24-a), connected to the Rotary Shaft (14), and,
   2. configured to induce rotation of the Rotary Shaft (14) about the Axis Of Rotation (15), with a continuous Direction Of Rotation (DR);
5. a Reflector Assembly (25), forming part of the Rotating Optical Assembly (22), composed of a plurality of n (at least two) Mirrors (M, M1, M2, ..., M11, M21, ..., M24 ), acting as an Optical Barrier (27), each of the Mirrors (M, M11) being configured so that, in certain rotational positions of the Rotating Optical Assembly (22),
   1. the Mirror (M) intercepts the Incoming Beam Axis (20), and,
   2. the Mirror (M) has a Reflection Point (29, 29-11), (i) positioned at a rotating Reflection Distance (32) perpendicular to the Rotation Axis (15), (ii) to reflect the Laser Beam Incoming (18) impacted on this Mirror (M), (iii) with a change in Angular Beam Direction (A), and, (iv) with a Reflection Efficiency (E) of the energy of the Incoming Laser Beam (18 ) substantially equal to one hundred per cent; And,
6. a Sensor-Assembly (33), composed of a plurality of p (at least two) Acoustic Electromagnetic Transducers (34) of the TEMA type, hereinafter referred to as TEMAs, including each Active Electromagnetic Probe (35):
   1. faces the Control Zone (3) and is substantially centered on a Detection Point (36) of the Control Zone (3), and,
   2. is configured to generate an A-Scan Signal (AS) detecting the position of the Faults (12, 13) versus time/distance, acquired from the Induced Signals (11) in the vicinity of its Detection Point (36);

This Device comprising a Rotating Optical Assembly (22) configured to have the following technical features:

1. the Rotating Optical Assembly (22) is geometrically configured such that when the Drive Motor (24-a) is activated,
   1. the Incoming Laser Beam (18) successively impacts a Reflection Point (29, 29-11) associated with and belonging to one of its n distant Mirrors (M, M11),
   2. each of the n Reflection Points (29, 29-11) of the n Mirrors (M), traverses a Circle Of Rotation (C, C-1, …, C-11, …), (i) of a Radius Of Rotation (37, 37-1… , 37-11…), (ii) centered on a Center Of Rotation (CR, CR-1, …, CR-11, ...) fixed on the Axis Of Rotation (15) ;
   3. the n different Mirrors (M, M1, M2, ..., M11, M21, ..., M24) redirect in an agile manner, successively and discontinuously the Incoming Laser Beam (18) according to a Collection of Secondary Beams (44), ( i) made of a bundle of n Secondary Laser Beams (45, 45-1, …, 45-11, …, 45-24) distant, (ii) resulting from a multitude of successive and discontinuous changes of the Angular Directions From Beam (A) of the Incoming Laser Beam (18), (iii) by reflection on the succession of n Mirrors (M) distant and in rotation;
2. the Rotating Optical Assembly (22) and its n Mirrors (M) are configured geometrically such that the n Secondary Laser Beams (45) successively generated impact an Impact Set (46) made of a multitude of n Impact Points (47, 47-1, …, 47-11…, 47-21, …, 47-24) distant, situated
   1. either on the Impact Plane (48), (i) facing the Rotating Optical Assembly (22), located on the Surface (4) of the Control Zone (3), and (ii) near a Sensing Point (36) of a TEMA Acoustic Electromagnetic Transducer (34), or,
   2. either on an Auxiliary Mirror (49, 49-21, …, 49-24);

This Device (1) being characterized in that it has the combination of the following technical features:

1. its Rotating Optical Assembly (22), including its n Mirrors (M), their mechanical connection parts and its associated n Reflection Points (29, 29-11), in rotation,
   1. is monolithic, that is to say made up of mechanical and/or optical parts all rigidly mechanically linked together and in a fixed position that cannot be modified with respect to each other, and,
   2. is rigidly fixed by Fixing Means (23) on the same Rotary Shaft (14), and
   3. to a rigid geometry that does not deform during its rotation;
2. the n Mirrors (M) of the Reflector Assembly (25) and their associated n Reflection Points (29, 29-11)
   1. are in a fixed position with respect to the same Axis Of Rotation (15), and,
   2. are set in synchronized rotation by the same Drive Motor (24-b);
3. during the rotation of the Rotating Optical Assembly (22) by the Drive Motor (24-a),
   1. the Rotating Reflection Distances (32) of the n Reflection Points (29, 29-11) of all the Mirrors (M), perpendicular to and with respect to the Rotation Axis (15), are all (i) constant and equal to each other during said rotation, and, (ii) substantially equal to Beam Distance (21);
   2. each of the n Reflection Points (29, 29-11) of the n Mirrors (M), traverses a Circle Of Rotation (C, C-1, …, C-11, …), (i) centered on the Axis Of Rotation (15), and (ii) held perpendicular to the Axis Of Rotation (15) during said rotation,
   3. each of the n Circles Of Rotation (C) (i) presents a projection, parallel to a projection plane parallel to the Axis Of Rotation (15) and passing through its Center Of Rotation (CR, CR-1, …, CR- 11, ...), formed by a Transverse Movement Segment (ST, ST-1, ..., ST-11, ...), perpendicular to the Axis Of Rotation (15) and centered on its Center Of Rotation (CR ), and, (ii) has a projection, parallel to a plane of rotation perpendicular to the Axis Of Rotation (15) and passing through its Center Of Rotation (CR, CR-1, ..., CR-11, ... ), formed by a Planar Projected Motion Circle (CP, CP-1, …, CP-11, …), merged with the Rotation Circle (C), and having a Projected Rotation Radius (RP, RP-1 , …, RP-11, …), equal to the Beam Distance (21) during said rotation;

In such a way that the Device (1) has the following geometric properties:

1. each Point of Reflection (29) of a Mirror (M) is positioned substantially in a fixed manner with respect to the same rotating Cylindrical Reflection Surface (38) of a Virtual Cylinder of Reflection (39) of revolution and rotation,
   1. with constant circular section,
   2. in rotation around the Axis Of Rotation (15),
   3. whose Radius Of Cylinder Of Reflection (41) is constant and substantially equal (i) to the Radii Of Rotation (37, 37-1, … , 37-11, …) of each of the n Circle Of Rotation (C, C-1 , …, C-11, …), and, (ii) Beam Distance (21),
   4. so that the cross-section of the Virtual Reflection Cylinder (39) of revolution and of its rotating Reflection Cylinder Surface (38) is constantly circular,
   5. but whose longitudinal position is fixed vis-à-vis the Rotary Shaft (14), that is to say without any longitudinal displacement vis-à-vis the axis Axis Of Rotation (15), when the Drive Motor (24-a) is activated;
2. the Points of Reflection (29) of each of its Mirrors (M) are positioned on a rotating Dotted Helical Line (43)
   1. with circular helical winding, of radius equal to the Beam Distance (21),
   2. and with a circular cylindrical screw thread,
   3. fixed as well as its points on the Cylindrical Reflection Surface (38), and in rotation with it, but,
   4. whose longitudinal position is fixed vis-à-vis the Rotary Shaft (14), that is to say without any longitudinal displacement vis-à-vis the Axis Of Rotation (15), when the Motor D 'Drive (24-a) is activated;
3. when the Drive Motor (24-a) is activated, the Incoming Laser Beam (18) is, during rotation, positioned substantially along successive rectilinear Reflection Generating Lines (42) of the Cylindrical Reflection Surface (38) rotary,
   1. each attached to a Reflection Point (29) of a Mirror (M),
   2. moving in rotation with the Virtual Cylinder of Reflection (39),
   3. but without longitudinal displacement with respect to the Axis Of Rotation (15).

A device (1) according to claim 1, characterized in that, in a Cylindrical Coordinate System (CCS), the Polar Cylindrical Axis (52) of which coincides with the Rotation Axis (15), and the Plane of Reference (53) is perpendicular to the Axis Of Rotation (15) and intersects it at some point of Origin (O) reference,

1. the Polar Angular Distances (Dθ) between the Angular Coordinates (θ) of two successive Reflection Points (29) of the Dotted Helical Line (43) joining all the Reflection Points (29) and circularly wound are positive and constant;
2. the Cylindrical Distances (r) of the Reflection Points (29) are constant and all equal to the Beam Distance (21); And,
3. the Circular Cylindrical Thread (57) of the Dotted Helical Line (43) is positive and constant.

A device (1) according to claim 2, characterized in that:

1. the constant Polar Angular Distances (Dθ) are substantially equal to 360° divided by the Number Of Mirrors (n), Dθ = 360° / n;

So that in the Cylindrical Coordinate System (CCS),

1. the Overall Reflection Length (Z), consisting of the difference between the Heights (z1, zn) of the two Extremal Mirrors (M1, Mn) farthest from the Rotating Optical Assembly (22), is substantially equal to the Screw Pitch (57) cylindrical Dotted Helical Line (43); And,
2. the Reflector Assembly (25) has an Angular Spectrum (AS) of Angular Coordinates (θ) covering substantially 360°.

A Device (1) according to Claim 1, characterized in that, when considering for each Mirror (M, M11) its Radial Segment (63), joining its Reflection Point (29) to its Projection Point (64) on the Axis Of Rotation (15); for each Mirror (M) and with respect to its Orientation Plane (65) passing through the Reflection Point (29, 29-11) and perpendicular to the Radial Segment (63):

1. the Radial Segment (63) has a constant Radial Length (62) equal to the Beam Distance (21),
2. the rotational Roll Angle (AR) relative to the Rotation Axis (15) is zero at 0°;
3. the Rotating Pitch Angle (AP) relative to the Rotation Axis (15) is the same for all Mirrors (M); And,
4. the longitudinal position of the Point of Projection (64) of each Radial Segment (63) is fixed along the Axis Of Rotation (15) and vis-à-vis the Rotary Shaft (14).

So that:

1. the Secondary Laser Beams (45),
   1. are all parallel and arranged along the same Secondary Beam Plane (68), passing through the Rotation Axis (15) and perpendicular to the Impact Plane (48); And,
   2. are arranged in a Plane Subbeam Array (69);
2. all the Impact Points (47) of the Control Zone (3) are aligned on a straight Dotted Impact Line (70) of the Impact Plane (48), and are separated by a certain Impact Distance (71) between two adjacent Impact Points (47).

A device (1) according to claim 4, characterized in that:

1. the rotary Pitch Angle (AP), with respect to the Rotation Axis (15), of each Mirror (M) is fixed equal to 45°, and,
2. the Control Zone (3) and the Impact Plane (48) are parallel to the Axis Of Rotation (15);

So that:

1. the Secondary Laser Beams (45) are each perpendicular to the Impact Plane (48); And,
2. the Secondary Length (72) of each of the Secondary Laser Beams (45), and therefore the Vertical Dimension (73) of the Rotating Optical Assembly (22) are minimized.

A Device (1) according to claim 1, characterized in that it is equipped with at least one digital B-Scan Processor (BSP), connected to the TEMA Acoustic Electromagnetic Transducers (34), configured for;

1. process and combine information from their detection A-Scan Signals (AS), and,
2. generate a two-dimensional digital B-Scan Presentation (75) of a section of the Metal Part (5),
   1. in a B-Scanning Plane (SAP) substantially coincident with the vertical Secondary Beam Plane (68), perpendicular to the Impact Plane (48) of the Control Zone (3) of the Metal Part (5),
   2. substantially along the Detection Line (77) joining the Dashed Impact Line (70), and,
   3. representing the Numerical Positions (78) with respect to the Depth (79) of the Discontinuities (12, 13) in the B-Scan Plane (SAP).

A device (1) according to claim 1, characterized in that:

1. its Rotating Optical Assembly (22) consists of a mechanical assembly of Support Sections (80) which are geometrically substantially identical, and arranged side by side along the Axis Of Rotation (15);
2. the Support Sections (80) are rigidly joined together,
3. a Mirror (M) is attached to each Support Section (80); And,
4. in the Cylindrical Coordinate System (CCS), whose Polar Cylindrical Axis (52) coincides with the Rotation Axis (15), two adjacent Support Sections (80) equipped with their Mirror (M), are rotated, the one relative to the other, perpendicular to the Rotation Axis (15), of the same Polar Angular Distance (Dθ) between two successive Reflection Points (29) belonging to their respective Mirrors (M) of the Helicoidal Line Dotted (43).

A device (1) according to claim 7, characterized in that:

1. its Support Sections (80) each have the form of an elongated Support Beam (81), the Support Axis (82) of which intersects the Rotation Axis (15);
2. each Support Beam (81) is fixed to the Rotating Shaft (14) by a Fixing Means (83);
3. a Mirror (M) is attached to a Support End (84) of each Support Beam (81).

A device (1) according to claim 7, characterized in that:

1. its Support Sections (80) are each substantially in the shape of a Flat Cylindrical Support Disc (85);
2. each Support Disc (85) is pierced with a Fixing Hole (86), formed perpendicularly and in its center, and whose Hole Diameter (87) is substantially equal to the diameter of the Rotary Shaft (14);
3. the Support Discs (85) are embedded side by side on the Rotary Shaft (14), along and in a stacking plane perpendicular to the Axis Of Rotation (15), by their Fixing Hole (86); And,
4. each Support Disc (85) is provided with a Support Housing (88), arranged on its Disc Periphery (89), on which its Mirror (M) is fixed.

A device (1) according to claim 7, characterized in that:

1. its Rotating Optical Assembly (22) is equipped with a Rigidity Assembly (90), consisting of a plurality of Rigid Rods (91),
   1. whose Rigidification Axis (92) is parallel to the Rotation Axis (15),
   2. fixed with respect to the Rotary Shaft (14), and fixed with respect to each other; And,
2. each Rigid Rod (91) passes through at least one Support Section (80); to which it is fixed rigidly by interlocking (93) in a stiffening recess (94) of this support section (80).

A device (1) according to claim 10, characterized in that:

1. the Rigid Rods (91) are arranged substantially along rectilinear Stiffening Generating Lines (95) of the same Virtual Stiffening Cylinder (96) of revolution, and,
2. the Stiffening Cylinder Axis (97) of the Virtual Stiffening Cylinder (96) coincides with the Rotation Axis (15).

A device (1) according to claim 11, characterized in that:

1. the Support Sections (80) of its Rotating Optical Assembly (22) each have the shape of Support Discs (85), geometrically identical and of flat cylindrical shape, arranged side by side, perpendicular and centered with respect to the Axis of Rotate (15);
2. each Support Disc (85) is provided with a Support Housing (88) formed on its Disc Periphery (89), on which its Mirror (M) is fixed;
3. its Rigidification Assembly (90) is formed of Rigid Rods (91) each consisting of a hollow Rigid Tube (98) rectilinear,
   1. internally sparing an empty Longitudinal Channel (99, 99-a) crossing it right through, along its Rigidification Axis (92), and,
   2. the Longitudinal Channel (99) of which is arranged substantially along a rectilinear Stiffening Generating Line (95) of the Virtual Stiffening Cylinder (96);
4. the distance of each Longitudinal Channel (99) with respect to the Axis Of Rotation (15) is constant, and substantially equal to the Radius Of Cylinder Of Reflection (41) and To The Distance Of Beam (21), so that the Virtual Cylinder of Rigidification (96) is substantially coincident with the Virtual Cylinder of Reflection (39) of revolution;
5. the Rigid Hollow Tubes (98; 98-a) are embedded in successive Disc Notches (100) provided on the Disc Periphery of certain Support Discs (85).

A device (1) according to claim 12, characterized in that:

1. its Stiffening Assembly (90) includes an Upstream Tubular Stiffening Assembly (90-a) consisting of Upstream Hollow Rigid Tubes (98-a), which have different Tube Lengths (101), and are geometrically configured such that 'they each extend longitudinally between,
   1. on the one hand, an Upstream Tube Upstream End (102-a), (i) located in the vicinity of the same Upstream Side Face (103-a) of the first Upstream Support Disc (104-a) of the Rotary Optical Assembly (22), (ii) through which the Incoming Laser Beam (18) penetrates perpendicularly,
   2. and on the other hand, an Upstream Tube Downstream End (105-a), placed opposite the Mirror (M) of a particular variable Intermediate Support Disc (106), different for each Upstream Hollow Rigid Tube (98-a);

Such that, when the Drive Motor (24-a) and the Incoming Laser Source (16) are activated:

1. the De-Rigidification Axes (92) of the Upstream Hollow Rigid Tubes (98-a) are in rotation along the rectilinear Reflection Generating Lines (42) of the Virtual Reflection Cylinder (39) of revolution;
2. Incoming Laser Beam (18)
   1. successively penetrates through the Longitudinal Channel (99) of one of the successive Upstream Hollow Rigid Tubes (98-a),
   2. and successively impacts the Reflection Point (29) of a Mirror (M) of a particular Intermediate Support Disk (106) facing it;
3. so that the Upstream Tubular Stiffening Assembly (90-a) simultaneously provides
   1. stiffening and immunity to longitudinal vibrations of the Rotating Optical Assembly (22), and,
   2. safety protection by encapsulating the Incoming Laser Beam (18) during rotation of the Rotating Optical Assembly (22).

A device (1) according to claim 13 characterized in that:

1. its Stiffening Assembly (90) further comprises a Downstream Tubular Stiffening Assembly (90-b), constituted by Downstream Hollowed Rigid Tubes (98-b), which have different Tube Lengths (101), and are geometrically configured so that they each extend longitudinally between,
   1. on the one hand, a Downstream Tube Upstream End (102-b), placed behind the Mirror (M) of a particular Intermediate Support Disc (106), different for each Downstream Hollowed Rigid Tube (98-b); And,
   2. on the other hand, a Downstream Tube Downstream End (105-b), located in the vicinity of the same Downstream Side Face (103-b) of the last Downstream Support Disc (104-b) of the Rotary Optical Assembly (22) ;
2. Upstream Tubular Stiffening Assembly (90-a) and Downstream Tubular Stiffening Assembly (90-b)
   1. have a similar topology, and, are complementary, and ,
   2. are substantially the image of each other, after mirror reflection combined with an axial rotation of 180°;

In such a way that :

1. the combination of the Upstream Tubular Stiffening Assembly (90-a) and the Downstream Tubular Stiffening Assembly (90-b)
   1. ensures rigidification and immunity to longitudinal vibrations of the Rotating Optical Assembly (22) over its entire length during its rotation, and,
   2. serves as a guide to allow easy assembly and angular indexing of the Support Discs (85); And,
2. the Downstream Hollowed Rigid Tubes (98-b) are never penetrated by the Incoming Laser Beam (18).

A device (1) according to claim 1, characterized in that:

1. it is equipped with a Focusing Assembly (107), consisting of a plurality of Focusing Lenses (108), fixed with respect to the Axis Of Rotation (15) and the Impact Plane (48) ; And,
2. these Focusing Lenses (108) are positioned between the Rotating Optical Assembly (22) and the Impact Plane (48), and their Optical Axis (109) is perpendicular to the Impact Plane (48).

A device (1) according to claim 15, characterized in that:

1. its Focusing Assembly (107) is equipped with Cylindrical Focusing Lenses (110) (of cylindrical or semi-cylindrical type) having an Optical Cylinder Axis (111) substantially parallel to the Impact Plane (48).

A Device (1) according to claim 16, characterized in that its Focusing Assembly (107) consists of Cylindrical Focusing Lenses (110),

1. each configured to focus the Secondary Laser Beams (45) passing through them,
   1. according to a narrow Rectangular Laser Impact Spot (112),
   2. i.e. whose Laser Spot Length (113) is at least twice its Laser Spot Width (114), and,
2. thus defining a Rectangular Spot Axis (115)
   1. oriented along the Laser Spot Length (113).

A device (1) according to claim 1, characterized in that:

1. it comprises a Secondary Support (116), in a fixed position with respect to the Axis Of Rotation (15) and the Impact Plane (48);
2. it comprises an Auxiliary Reflector Assembly (117, 117-a), composed of at least two (q) Auxiliary Mirrors (49, 118, 118-a-1, 118-a-2, 118-a-3),
   1. each being in a fixed position between them and vis-à-vis the Secondary Support (116), and,
   2. geometrically configured to deviate by successive reflections Auxiliary Laser Beams (119, 119-a-1, 119-a-2, 119-a-3, 119-a-4) from an Auxiliary Beam Collection (120, 120-a , 120-b, 120-c, 120-d), whose first deflected beam (119-a-1) consists of one of the Secondary Laser Beams (45, 45-21) emitted by the Rotating Optical Assembly ( 22);
   3. which are each successively impacted by one of the Auxiliary Laser Beams (119, 119-a-1, 119-a-2, 119-a-3) at an Auxiliary Reflection Point (121, 121-a-1, 121-a -2, 121-a-3) of this Auxiliary Mirror (118, 118-a-1, 118-a-2, 118-a-3 ) to constitute a new Auxiliary Laser Beam deflected from the Auxiliary Beams Collection (120, 120-a, 120-b, 120-c, 120-d), each time with a change of Angular Beam Direction (A) of this Auxiliary Laser Beam (119, 119-a-1, 119-a-2, 119-a-3) impacting;
3. an Upstream Auxiliary Mirror (122, 118-a-1) of the Auxiliary Reflector Assembly (117, 117-a) is positioned in the path of a Secondary Laser Beam (45, 45-21); and is geometrically configured
   1. to be impacted by this Secondary Laser Beam (45, 45-21), on its Auxiliary Reflection Point (121, 121-a-1);
   2. and to reflect it into a first Auxiliary Laser Beam (119, 119-a-2) deflected from the Auxiliary Beam Collection (120, 120-a);
4. a Downstream Auxiliary Mirror (123, 118-a-3) of the Auxiliary Reflector Assembly (117, 117-a) is geometrically configured,
   1. to substantially face both (i) the last Auxiliary Laser Beam (119, 119-a-3) of the Auxiliary Beam Collection (120, 120-a), and (ii) the Control Zone (3); And,
   2. to deflect this last Auxiliary Laser Beam (119, 119-a-3), according to an ultimate Deviated Secondary Laser Beam (124, 119-a4, 124-a), which impacts, downstream of the Auxiliary Beam Collection (120, 120 -a), a Deviated Impact Point (125, 125-a) from the Impact Plane (48) of the Control Zone (3) adjacent to a Detection Point (36) of a TEMA Acoustic Electromagnetic Transducer (34).

A device (1) according to claim 18, characterized in that:

1. it comprises Auxiliary Reflector Assembly (126, 126-1), consisting of at least two Auxiliary Reflector Assemblies (117, 117-a, 117-c),
2. said at least two Auxiliary Reflector Assemblies (117, 117-a, 117-c) are geometrically configured such that their at least two Deflected Secondary Laser Beams (124, 124-a, 124-c),
   1. are parallel and arranged according to the same Deflected Secondary Beam Plane (127, 127-1),
   2. are substantially perpendicular to the Impact Plane (48),
   3. are arranged in a Planar Array Of Deviated Secondary Beams (128, 128-1), and,
   4. impact a Deflected Impact Set (129, 129-1) made up of at least two distant Deflected Impact Points (125, 125-a, 125-c), arranged on a Dotted Line of Deflected Impacts (130, 130- 1) straight from the Impact Plane (48) to the Control Zone (3).

A device (1) according to claim 19, characterized in that:

1. it is equipped with a Focusing Assembly (107) consisting of Focusing Lenses (108), fixedly positioned with respect to the Axis Of Rotation (15) and the Impact Plane (48); And,
2. the Focusing Lenses (108) are geometrically configured in two groups, according to the positioning of their Optical Axes (109), including;
   1. a first group made of Secondary Focusing Lenses (131), (i) whose Secondary Optical Axis (132) coincides with the Secondary Axis (133) of a Secondary Laser Beam (45), originating from the Reflection Point (29) of a rotating Mirror (M), and (ii) in this case it is fixed vis-à-vis the Rotation Axis (15), between the Virtual Reflection Cylinder (39) of revolution and the Point of Impact (47) of this Secondary Laser Beam (45), and, (iii) configured to focus this Secondary Laser Beam (45) on its Point of Impact (47) of the Dotted Line of Impact (70) , And,
   2. a second group made of Auxiliary Focusing Lenses (134), (i) whose Auxiliary Optical Axis (135) coincides with the Auxiliary Axis (136) of an ultimate Secondary Deviated Laser Beam (124), coming from the Point Auxiliary Reflection Mirror (121, 121-b-3) end of a Downstream Auxiliary Mirror (123, 118-b-3), and (ii) in this case it is fixed with respect to the Rotation Axis (15), between the Virtual Reflection Cylinder (39) of revolution and the Deflected Impact Point (125, 125-b) of the Deflected Secondary Laser Beam (124, 124-a), and, (iii) configured to focus this Deviated Secondary Laser Beam (124, 124-b) on its Deviated Impact Point (125, 125-b) of a Dotted Line Of Deflected Impacts (130, 130-2).

A device (1) according to claim 20, characterized in that:

1. its Focusing Assembly (107) consists of Cylindrical Focusing Lenses (110),
   1. fixed with respect to the Secondary Support (116);
   2. having an Optical Cylinder Axis (111) substantially parallel to the Impact Plane (48),
   3. each configured to focus a Secondary Laser Beam (45) or a Deflected Secondary Laser Beam (124) along a Rectangular Laser Impact Spot (112) on the Impact Plane (48), along a Rectangular Spot Axis (115) ;
2. these Cylindrical Focusing Lenses (110) are geometrically configured such that the Focusing Assembly (107) is divided into two groups:
   1. on the one hand, a Longitudinal Focusing Collection (137), consisting of Longitudinal Cylindrical Focusing Lenses (138), that is to say whose Optical Cylinder Axis (111) is substantially longitudinal with respect to of the Axis of Rotation (15), which are configured to focus a beam of light passing therethrough onto a Longitudinal Rectangular Laser Impact Spot (139), and,
   2. on the other hand, a Transversal Focusing Collection (140), consisting of Transverse Cylindrical Focusing Lenses (141), that is to say whose Optical Cylinder Axis (111) is substantially transverse with respect to of the Axis of Rotation (15), which are configured to focus a beam of light passing therethrough onto a Transverse Rectangular Laser Impact Spot (142).

A device (1) according to claim 21, characterized in that:

1. It includes both:
   1. a Plane Secondary Beam Array (69), consisting of Secondary Laser Beams (45, 45-11), (i) emitted by the Rotating Optical Assembly (22), (ii) which impact the Points of Impact (47) the Dashed Impact Line (70), and,
   2. at least one Planar Array Of Deflected Secondary Beams (128, 128-1, 128-2), consisting of Deflected Secondary Laser Beams (124, 124-a-21, 124-b-22, 124-c-23, 124- d-24), (i) from an Auxiliary Reflector Assembly (126, 126-1, 126-2), (ii) which impact the Deflected Impact Points (125, 125-a-21, 125-b -22, 125-c-23, 125-d-24) of at least one Dotted Line Of Deviated Impacts (130, 130-1, 130-2);
2. The Longitudinal Cylindrical Focusing Lenses (138), and the Transverse Cylindrical Focusing Lenses (141) are positioned complementary and exclusively in two groups, so that:
   1. a first group (110-1) focuses the Plane Secondary Beam Array (69) on its Impact Dotted Line (70), (i) only along Longitudinal Rectangular Laser Impact Spots (139), or (ii) only according to Transverse Rectangular Laser Impact Spots (142); And,
   2. alternatively, and exclusively from the previous one, a second group (110-2) focuses the Plane Array Of Deviated Secondary Beams (128, 128-1, 128-2) on a Dotted Line Of Deviated Impacts (130, 130- 1, 130-2), (i) only according to Transverse Rectangular Laser Impact Spots (142), or (ii) only according to Longitudinal Rectangular Laser Impact Spots (139).

A device (1) according to claim 1, characterized in that:

1. its Sensor Assembly (33) is composed of Directional TEMAs (143), of the type presenting a Preferred Directional Orientation Of Capture (144) of Induced Signals (11) generated by the interaction of Mechanical Vibrations (8) with Surface Discontinuities ( 12) and Subsurface Discontinuities (13);
2. its Sensor Assembly (33) is configured to be divided into two groups,
   1. on the one hand a Collection Of Longitudinal Sensors (145), consisting of Longitudinal TEMAs (146, 146-T, 146-D), that is to say with Preferred Directional Orientation Of Capture (144) according to a longitudinal direction opposite -towards the Axis Of Rotation (15), and,
   2. on the other hand, a Collection Of Transversal Sensors (147), consisting of Transversal TEMAs (148, 148-T, 148-D), that is to say with Privileged Directional Orientation Of Capture (144) according to a transverse direction opposite -towards the Axis Of Rotation (15);
3. the Transverse Rectangular Laser Impact Spots (142, 15-a-21, 125-b-22, 125-c-23, 125-d-24) are (in number) mainly located between two Longitudinal TEMAs (146); And,
4. Longitudinal Rectangular Laser Impact Spots (139, 47-11) are (in number) predominantly located adjacent to and above or below Transverse TEMAs (148), with reference to a height positioning orientation taken perpendicular to the Axis Of Rotation (15).

A Device (1) according to claim 20, characterized in that its Rotating Optical Assembly (22) is geometrically configured so that:

1. it includes both:
   1. a Planar Array Of Secondary Beams (69), (i) consisting of Secondary Laser Beams (45, 45-11), (ii) which impact the Impact Points (47) of the main Impact Dotted Line (70) ,
   2. two Planar Arrays Of Deviated Secondary Beams (128, 128-1, 128-2), (i) consisting of two groups of Deviated Secondary Laser Beams (124-a, 124-c) and (124-b, 124-d) , (ii) from two Auxiliary Reflector Assemblies (126, 126-1, 126-2), (iii) which impact two distant auxiliary Deviated Impact Dotted Lines (130, 130-1, 130-2), and,
2. the main Impact Dotted Line (70) and the two auxiliary Deflected Impact Dotted Lines (130, 130-1, 130-2) are all three parallel to the Rotation Axis (15) and distant from each other; And,
3. the two Dashed Impact Lines (130, 130-1, 130-2) are located on either side, i.e. above and below the Dashed Impact Line (70) main, referring to a height positioning orientation taken perpendicular to the Axis Of Rotation (15).

A Device (1) according to claim 24, characterized in that its Rotating Optical Assembly (22) is geometrically configured so that:

1. its main Impact Dotted Line (70) is formed by Longitudinal Rectangular Laser Impact Spots (139); And,
2. its two auxiliary Deviated Impact Dotted Lines (130, 130-1, 130-2) are formed by Transverse Rectangular Laser Impact Spots (142, 125-a-21, 125-b-22, 125-c-23 , 125-d-24).

A Device (1) according to claims 23 and 25, characterized in that its Rotating Optical Assembly (22) is geometrically configured so that:

1. its Longitudinal TEMAs (146, 146-T, 146-D) are mostly (in number)
   1. aligned on either side and in an alternating manner vis-à-vis the main Dotted Impact Line (70), and,
   2. positioned longitudinally next to a Transverse Rectangular Laser Impact Spot (142, 125-a-21, 125-b-22, 125-c-23, 125-d-24) of one of the two Dotted Lines D' Deflected hits (130, 130-1, 130-2); And,
2. its Transverse TEMAs (148, 148-T, 148-D) are predominantly (in number) positioned and aligned alternately above and/or below the Longitudinal TEMAs (146, 146-T, 146-D), with reference to a height positioning orientation taken in a direction perpendicular to the Axis Of Rotation (15).

A device (1) according to claim 1, further comprising:

1. Angular Position Control Means (149) of the single Rotating Shaft (14), and therefore of the Rotating Optical Assembly (22) monolithic in rotation with respect to the Rotation Axis (15);
   1. connected to the single Rotary Shaft (14);
2. Means Of Control And Timing Of The Laser Pulses (150),
   1. electrically connected to the Incoming Laser Source (16),
   2. and configured to control and/or clock the generation of laser pulses by the Incoming Laser Source (16);
3. Engine Rotation Timing Means (151),
   1. electrically connected to the Drive Motor (24-a);
4. a Laser Rotation Pulse Synchronized Timing Processor (152),
   1. electrically connected to the Angular Position Control Means (149) of the Rotary Shaft (14), and,
   2. electrically connected to the Motor Rotation Timing Means (151), for continuously receiving the angular position of the Rotary Shaft (14);

Said Device (1) being characterized in that the Laser Rotation Pulse Synchronized Timing Processor (152) is configured:

1. either in Motor Control Mode (153),
   1. to electrically drive the Engine Rotation Timing Means (151),
   2. depending on the timing of the laser pulses generated by the Incoming Laser Source (16),
   3. this in order to successively adaptively position the axial angular position of the Rotating Optical Assembly (22),
   4. so that the Number of Mirror Impact Pulses (NIM) of the pulses of the Incoming Laser Beam (18) impacting each of the Mirrors (M, M1, ..., M20) in rotation, in the vicinity of its Reflection Point (29) of the Rotary Dotted Helical Line (43), either constant (for example NIM =2); Or,
2. either in Pulse Control Mode (154),
   1. to electrically drive the Laser Pulse Control And Timing Means (150),
   2. depending on the timing of the axial angular position of the Rotating Optical Assembly (22), continuously received from the Angular Position Control Means (149),
   3. this in order to successively adapt the timing of the pulses of the Incoming Laser Beam (18),
   4. so that the Number of Mirror Impact Pulses (NIM) of the pulses of the Incoming Laser Beam (18) impacting each of the Mirrors (M, M1, ..., M20) in rotation, in the vicinity of its Reflection Point (29) of the Dotted Helicoidal Line (43) rotating, or constant (for example NIM =2).